The quest for stronger, more versatile ceramic products is an ongoing, very important concern. Difficulties exist, for instance, in providing sufficiently strong, finished ceramic bodies that would conform to precise and intricate geometries. In light of this, many ceramic products, which would be highly desirable, remain unavailable.
For example, although an alumina femoral knee component is known from Japan, it is made in a manner only to address the most basic of femoral implant designs, and problems with it include its great expense, as it may be made by machining a fired block. Attempts to provide ceramic advanced femoral knee components apparently have met with failure, and such more intricate ceramic implants that require great strength are lacking in the art. As an example of such an implant is a posterior stabilized femoral component for a knee implant. In fact, experts in the art are skeptical that such can be made. Note, too, Amino et al., U.S. Pat. No. 5,549,684.
It would be desirable to overcome such difficulties. It would be desirable, moreover, to provide an efficient and cost effective method to do the same.
In a particularly notable implant provision, Goodman et al., U.S. Pat. No. 5,766,257, discloses an artificial joint having natural load transfer. In a particular embodiment, the joint is a knee. Although it is disclosed that a ceramic substance may be employed, preferably the joint is of metal construction. For example, its femoral component frame is a cast or forged cobalt-chromium alloy, and its tibial component frame is a titanium alloy, with a Co—Cr alloy rotation device and bearings of ultra high molecular weight polyethylene (UHMWPE). See also, Zimmer, Inc., NexGen (Reg. U.S. Pat. & Tm. Off.) System Rotating Hinge Knee Design Rationale, 2002.
Additional modularity may be provided in such a knee implant. See, Serafin, Jr., U.S. Pat. No. 6,629,999.
Employment of ceramic in bodily implants, to include a posterior stabilized femoral component and the knee implants of the '257 and '999 patents as well as other implants could be of benefit. For example, certain patients are allergic to slight amounts of Nickel found in Co—Cr alloys, and ceramic may provide for a hard articulating surface. However, for such complex knee implant components as noted above in particular, a more practical application of the basic concept of employing ceramics is needed.
Serafin, Jr., et al., in WO 2004/080340, the publication of the mentioned '908 application, disclose ceramic manufactures. Therein, a ceramic body can be made by providing an initial green body of ceramic, machining it, and firing it.
Other ceramic making art is known. For example, Bodenmiller et al., in U.S. Pat. No. 6,495,073, disclose a method for the manufacture of medical, dental-medical, dental-technical and technical parts from ceramics. Therein, a powdery raw ceramic is compressed to form a ceramic green compact, and the compact is embedded in an embedding mass, for example, a wax, and machined in the embedding mass. After machining, the part is de-waxed, and fired. Among drawbacks to such methodology, however, is that embedding mass wax can gum up or clog machining tools.
It would be desirable to avoid embedding mass wax in ceramic work, in general, and, in various cases, avoid or limit wax use.